1. Field of the Invention
This invention relates to an antenna device.
2. Description of the Related Art
Conventionally, an antenna device is known that is equipped with a transmission line having a triplate structure composed of one pair of plate-shaped conductors and a central conductor located between the one pair of plate-shaped conductors, and a plurality of antenna elements each capable of transmitting a high frequency signal distributed by that transmission line. (See JP-A-2014-110557 (FIG. 5))
The antenna device disclosed in JP-A-2014-110557 (FIG. 5) includes a plate-shaped first outer conductor, a plate-shaped second outer conductor, which is spaced a predetermined distance apart from the first outer conductor, a linear central conductor, which is disposed between the first outer conductor and the second outer conductor, and a plurality of (eight) antenna elements. The central conductor is branched sequentially from an input side, divided into eight terminals on an output side, and connected to the antenna elements at each terminal. When a high frequency signal is then provided at the input side, a radio wave depending on that high frequency signal is radiated from the plurality of antenna elements.
In this manner, constructing the high frequency signal distributing lines by using the triplate line allows for reducing dielectric loss, and simplifying the line configuration and assembling, in comparison to when using a coaxial cable, for example.